If you are interested in hCG, like we are, you might be interested in a recent paper, in Clinical Chemistry, by Dr. Glenn Braunstein entitled "The long gestation of the modern home pregnancy test."
Dr. Braunstein is one of the researchers that helped develop the first radioimmunoassay specific for hCG in the 1970's and is a leader in the field of hCG.
In his paper, Dr. Braunstein reflects on the history of urine pregnancy tests. He explains that there is actually a description of a pregnancy test in ancient Egyptian papyrus writings. In that test, women urinate on wheat and barley seeds. If neither grows the woman is not pregnant. If the barley grows it will be a male and if the wheat grows it will be a female!
The first bioassay was described in 1927 by the German scientists Ascheim and Zondek who demonstrated ovarian stimulation in mice when they were injected with the urine from pregnant women. After that, there were many bioassays developed to detect pregnancy. Apparently these had analytical sensitivities of between 100-18,000 IU/L and they took 2-9 days to get a result!
The first radioimmunoassay for hCG & LH (leuteinizing hormone) was described in 1966 by Midgley. Its analytical sensitivity was very high by today’s standards (175 IU/L) but, of course, it recognized both hCG and LH and it took 3 days to perform. The similarity between hCG and LH was a real problem. It was not until Dr. Braunstein, together with Dr. Judith Vaitukaitis, developed new antibodies that were specific to the hCG beta subunit that an hCG-specific assay was developed. With this assay, they were able to detect pregnancy as early as 7.5 days after fertilization and they were able to develop reference intervals for serum during pregnancy.
The first home pregnancy test marketed in the U.S. was the e.p.t.® ("Early pregnancy test") in 1977. It was described as a "private little revolution" because it allowed women to determine if they were pregnant in the privacy of their own home with no one else knowing. Today, pregnancy tests account for $228 million dollars in annual sales and take up considerable shelf space at retail stores with different brands and styles (see photo).
For further reading, another great reference for the history of the pregnancy test was created by the NIH library and can be found here.